A Study to Investigate the Efficacy and Safety of S-888711 Tablets Administered to Adult Subjects With Immune Thrombocytopenia (ITP)

Inclusion Criteria:

- A signed and dated written informed consent

- Males and females ≥ 18 years of age

- All subjects must agree to use barrier contraception

- Diagnosis of ITP

- Subjects > 60 years must have had a diagnostic bone marrow aspiration

- Relapsed persistent or chronic ITP status, with or without prior splenectomy
(exception: in Hungary only splenectomized subjects will be enrolled), after having
failed at least 1 prior ITP therapy (excluding TPO agonists) and have a platelet count
< 30,000/μL if not taking medications or < 50,000/μL despite concomitant steroids or
other ITP therapies, such as danazol or immunosuppressive drugs

- Subjects receiving steroid therapy must be on a stable dose

- PT and APTT within 20% of the upper limit of normal

- Subjects receiving stable dosages of cyclosporine A, mycophenolate mofetil,
azathioprine, or danazol are allowed. The dosages of all these medications must be
stable for at least 4 weeks prior to Visit 1 (Day 1)

Exclusion Criteria:

- History of clinically important hemorrhagic clotting disorder

- Females who are pregnant, lactating, or taking oral contraceptives

- History of alcohol/drug abuse or dependence within 1 year

- Use of the following drugs or treatment prior to Visit 1 (Day 1):

- Within 12 weeks - alemtuzumab, multi-drug systemic chemotherapy, stem cell
therapy;

- Within 8 weeks - rituximab

- Within 2 weeks - platelet transfusions or plasmapheresis treatment

- Within 4 weeks - use of anti-platelet or anti-coagulant drugs

- Within 1 week - Rho(D) immune globulin or intravenous immunoglobulin

- History of clinically significant cardiovascular or thromboembolic disease within 26
weeks prior to Screening

- Splenectomy within 4 weeks prior to Screening

- Clinically significant laboratory abnormalities

- Hemoglobin < 10.0 g/dL for men or women, not clearly related to ITP

- Absolute neutrophil count < 1000/mm3

- Abnormal peripheral blood smear

- Total bilirubin > 1.5 x upper limit of normal

- Alanine aminotransferase (ALT) > 1.5 x upper limit of normal

- Aspartate aminotransferase (AST) > 1.5 x upper limit of normal

- Creatinine > 1.5 x upper limit of normal

- Human immunodeficiency virus (HIV) positive

- Hepatitis A IgM antibody (IgM HAV) positive, hepatitis B surface antigen (HbsAg)
or hepatitis C antibody (HCV) positive

- Thyroid stimulating hormone (TSH) > 1.5 x upper limit of normal

- Free thyroxine (T4) > 1.5 x upper limit of normal

- Exposure to previous TPO mimetics/agonists (e.g., eltrombopag,romiplostim, E5501
[AKR-501] or LGD-4665) within 4 weeks prior to Screening

- Subjects unresponsive to previous TPO mimetics/agonists (e.g., eltrombopag,
romiplostim, E5501 [AKR-501] or LGD-4665)

- Exposure to an investigative medication within the past 30 days